Can I institute legal proceedings against a doctor or hospital

My son, 16 years old, had a major motorbike accident and survived, but with serious injuries to his leg. He had fractured his leg and was rushed to a nearest trustee private hospital. The doctor on call said that he has multiple fractures on his leg had had to operate on him, this operation was delayed for 3 days. During the operation we (the parents) were called to the operation theater, only to be told that our son had multiple fractures on his leg and would have to live with a stiff leg for the rest of his life. The doctor did not give us any hope whatsoever, and even showed us in an act how our son would be stuck with a stiff leg. He latter added that he could fuse the knee joint permanently so as to provide a slight bend. Luckily for us, this operation was a failure, because after the surgery, our son was complaining of severe pain. On taking an X-ray it was noticed that a bone in the knee was jetting out because it was not screwed in correctly. The plate (rod) was not fixed properly too. So the doctor said that he would have to operate again. At this, we decided to take a second opinion. We took him off from that hospital and got him admitted to another hospital, where the doctors there confirmed that the previous operation was not done correctly. Further, it was realized that my son had succumbed to another fracture in the hip which was not detected in the previous hospital !!! Can you imagine that he was not diagnosed properly in the previous hospital after having a fatal accident? Two surgeries were carried out in the second hospital, and my son is now well and OK, still walking with the help of a walker, but he can bend his knee to 90% and it will get better with physiotherapy. We have not approached the first hospital and told them that since the operation was a failure here we had spent 2.7 L and would like that monies back as we did not benefit from that hospital, but they only caused us more pain and trauma to us and to our child...who was also told by the doctor that he would not be able to walk properly again. We do not have that kind of money which was paid partly by my insurance, but for the second and third operation, we had to take loans from relatives and others. We need some help now on how we can sue the doctor or the hospital or both..if they don't agree to give back our money, Please advise.